'Oh my God': Coach loses his mind after Ariarne Titmus' gold

The swimming coach of Ariarne Titmus has captured the hearts of viewers around the world after an extraordinary reaction to the Aussie superstar's stunning 400m freestyle victory at the Tokyo Olympics.

The 20-year-old triumphed in a titanic final on Monday, defeating the United States' five-time Olympic champion Katie Ledecky.

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Titmus' achievement is Australia's second gold medal of the Tokyo Games, following the women's 4x100m freestyle relay success.

And it delivers Ledecky, regarded as the greatest female swimmer ever, her first defeat in an Olympic final.

Titmus trailed for most of the race but reeled in the American champion at the end - touching in a time of three minutes 56.69 seconds.

Ledecky came home in 3:57.36 and China's Li Bingjie was well back in third position in 4:01.08.

The epic swim from Titmus drew praise from Aussie fans around the world, but nobody was more excited than her coach, Dean Boxall, who was riding the race all the way to the finish line.

The swimming mentor jumped up and roared in celebration after Titmus claimed gold, before grabbing hold of a rail and shaking it maniacally as the emotion of the moment overwhelmed him.

Boxall's extraordinary reaction quickly went viral as Olympic fans hailed the passion he showed for his swimmer.

Aussie beats one of the greatest ever

Titmus, in lane three, kept watch on Ledecky in lane four in what became the utimate match race between the pair.

Ledecky is regarded as arguably the greatest female swimmer of all time over the longer distances and she lay down the gauntlet to Titmus.

The American held the lead for the initial 300m but Titmus was watching her all the way, literally lurking at her heels.

The young Australian ominously surged closer and was just 0.16 seconds behind Ledecky with 100m remaining.

Titmus then reeled in her rival in a perfectly-executed race plan to win by half a body-length in a time of three minutes 56.69 seconds.

Ledecky touched home in 3:57.36 and China's Li Bingjie was well back in third position in 4:01.08.

Titmus and Ledecky will also square off in a much-hyped 200m freestyle battle, though the American is favoured to win their duel over 800m.

with agencies

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